An object in about 800 feet of water outside the mouth of Pearl Harbor might be a Japanese submarine believed sunk hours before the attack on Dec. 7, 1941, authorities said.

"It could be anything," said Bill Dickinson, superintendent of the USS Arizona Memorial Park. "Even a bunch of oil drums in a line. But it looks promising."

Sonar pings produced a shape that matches what is known about midget submarines involved in the Japanese attack, Dickinson said, adding that it was in a "high probability area" for the midget sub.

"It's going to take a lot more to confirm what's down there," he said. "First, we have to locate the resources to pay for a search and then convince the University of Hawaii or National Geographic or somebody else with deep-diving equipment to go down and take a look."

"That's the only way the mystery will be solved," he said.